Simplify predication constructions involving the INT_OR operator. More...

#include <condexe.hh>

Inheritance diagram for RuleOrPredicate:

Classes
struct	MultiPredicate
	A helper class to mark up predicated INT_OR expressions. More...

Public Member Functions
	RuleOrPredicate (const string &g)
	Constructor.

virtual Rule *	clone (const ActionGroupList &grouplist) const
	Clone the Rule. More...

virtual void	getOpList (vector< uint4 > &oplist) const
	List of op codes this rule operates on. More...

virtual int4	applyOp (PcodeOp *op, Funcdata &data)
	Attempt to apply this Rule. More...

Public Member Functions inherited from Rule
	Rule (const string &g, uint4 fl, const string &nm)
	Construct given group, properties name. More...

virtual	~Rule (void)
	Destructor.

const string &	getName (void) const
	Return the name of this Rule.

const string &	getGroup (void) const
	Return the group this Rule belongs to.

uint4	getNumTests (void)
	Get number of attempted applications.

uint4	getNumApply (void)
	Get number of successful applications.

void	setBreak (uint4 tp)
	Set a breakpoint on this Rule.

void	clearBreak (uint4 tp)
	Clear a breakpoint on this Rule.

void	turnOnWarnings (void)
	Enable warnings for this Rule.

void	turnOffWarnings (void)
	Disable warnings for this Rule.

bool	isDisabled (void) const
	Return true if this Rule is disabled.

void	setDisable (void)
	Disable this Rule (within its pool)

void	clearDisable (void)
	Enable this Rule (within its pool)

bool	checkActionBreak (void)
	Check if an action breakpoint is turned on. More...

uint4	getBreakPoint (void) const
	Return breakpoint toggles.

virtual void	reset (Funcdata &data)
	Reset this Rule. More...

virtual void	resetStats (void)
	Reset Rule statistics. More...

virtual void	printStatistics (ostream &s) const
	Print statistics for this Rule. More...

Private Member Functions
int4	checkSingle (Varnode vn, MultiPredicate &branch, PcodeOp op, Funcdata &data)
	Check for the alternate form, tmp1 = (val2 == 0) ? val1 : 0;. More...

Additional Inherited Members
Public Types inherited from Rule
enum	typeflags { type_disable = 1, rule_debug = 2, warnings_on = 4, warnings_given = 8 }
	Properties associated with a Rule. More...

Detailed Description

Simplify predication constructions involving the INT_OR operator.

In this form of predication, two variables are set based on a condition and then ORed together. Both variables may be set to zero, or to some other value, based on the condition and the zero values are such that at least one of the variables is zero.

tmp1 = cond ? val1 : 0;
tmp2 = cond ?  0 : val2;
result = tmp1 | tmp2;

The RuleOrPredicate simplifies this to

if (cond) result = val1; else result = val2;

or to be precise

newtmp = val1 ? val2; // Using a new MULTIEQUAL

result = newtmp;

In an alternate form we have

tmp1 = (val2 == 0) ? val1 : 0

result = tmp1 | val2;

again, one of val1 or val2 must be zero, so this gets replaced with

tmp1 = val1 ? val2

result = tmp1

Member Function Documentation

◆ applyOp()

int4 RuleOrPredicate::applyOp	(	PcodeOp *	op,
		Funcdata &	data
	)

virtual

Attempt to apply this Rule.

This method contains the main logic for applying the Rule. It must use a given PcodeOp as the point at which the Rule applies. If it does apply, changes are made directly to the function and 1 (non-zero) is returned, otherwise 0 is returned.

Parameters

op	is the given PcodeOp where the Rule may apply
data	is the function to which to apply

Reimplemented from Rule.

◆ checkSingle()

int4 RuleOrPredicate::checkSingle	(	Varnode *	vn,
		MultiPredicate &	branch,
		PcodeOp *	op,
		Funcdata &	data
	)

private

Check for the alternate form, tmp1 = (val2 == 0) ? val1 : 0;.

We know we have the basic form

tmp1 = cond ? val1 : 0;

result = tmp1 | other;

So we just need to check that other plays the role of val2. If we match the alternate form, perform the simplification

Parameters

vn	is the candidate other Varnode
branch	holds the basic form
op	is the INT_OR p-code op
data	is the function being analyzed

Returns: 1 if the form was matched and simplified, 0 otherwise

References CPUI_COPY, RuleOrPredicate::MultiPredicate::discoverCbranch(), RuleOrPredicate::MultiPredicate::discoverConditionalZero(), RuleOrPredicate::MultiPredicate::discoverPathIsTrue(), PcodeOp::getOut(), Varnode::isFree(), Varnode::loneDescend(), RuleOrPredicate::MultiPredicate::op, Funcdata::opRemoveInput(), Funcdata::opSetInput(), Funcdata::opSetOpcode(), RuleOrPredicate::MultiPredicate::zeroPathIsTrue, and RuleOrPredicate::MultiPredicate::zeroSlot.

Referenced by applyOp().

◆ clone()

virtual Rule* RuleOrPredicate::clone ( const ActionGroupList & grouplist ) const

inlinevirtual

Clone the Rule.

If this Rule is a member of one of the groups in the grouplist, this returns a clone of the Rule, otherwise NULL is returned.

Parameters

grouplist is the list of groups being cloned

Returns: the cloned Rule or NULL

Implements Rule.

References ActionGroupList::contains(), Rule::getGroup(), and RuleOrPredicate().

◆ getOpList()

void RuleOrPredicate::getOpList ( vector< uint4 > & oplist ) const

virtual

List of op codes this rule operates on.

Populate the given array with all possible OpCodes this Rule might apply to. By default, this method returns all possible OpCodes

Parameters

oplist is the array to populate

Reimplemented from Rule.

References CPUI_INT_OR, and CPUI_INT_XOR.

The documentation for this class was generated from the following files:

condexe.hh
condexe.cc

Classes

Public Member Functions

Private Member Functions

Additional Inherited Members

Detailed Description

Member Function Documentation

◆ applyOp()

◆ checkSingle()

◆ clone()

◆ getOpList()